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Carbon and its Compounds

An ester and an alkali

Soap is made from fat or oil and an alkali. An alkali is a base that dissolves in water. The reaction has a name.

An ester meets sodium hydroxide, an alkali.
Step 1 of 4
  1. An ester meets sodium hydroxide, an alkali.
  2. The ester breaks.
  3. It gives an alcohol and the sodium salt of the acid.
  4. The sodium salt of a long-chain acid is a soap.

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Read the two reactants. Tap the name of the reaction.

The rule

An ester and sodium hydroxide make an alcohol and a salt. The salt is the sodium salt of the acid. This is saponification. Fats and oils treated this way give soap.

CH₃COOCH₃ + NaOH → CH₃OH + CH₃COONa

This reaction is saponification. It breaks an ester into an alcohol and a salt.

Fats and oils are esters of long-chain acids. The sodium salts of those acids are soaps.

Three reactions of an acid or an ester
StartAddName
AcidAlcoholEsterification
EsterSodium hydroxideSaponification
AcidSodium hydroxideNeutralisation

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This track

  1. 0 Start here
  2. 1 The bond that shares
  3. 2 Why carbon builds everything
  4. 3 Single or double
  5. 4 One part swapped
  6. 5 A family with one difference
  7. 6 Ethanol
  8. 7 Ethanoic acid
  9. 8 Soaps bridge oil and water
  10. 9 Naming a compound
  11. 10 An acid and an alcohol make an ester
  12. 11 An ester and an alkali
  13. 12 Checkpoint: bonds, names and esters
  14. 13 The big picture
  15. 14 Track quiz

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